1. Field of the Invention
The present invention is directed to a method and apparatus for the presentation of images reproducible at a display monitor, wherein digital image data of an examination volume of a subject are registered with an image pick-up system such as preferably, a medical examination installation.
2. Description of the Prior Art
Particularly in the field of medical examinations, images of an examination subject that are displayed at a monitor are registered, so that the physician can view them and make a diagnosis based thereon. For example, such images can be registered with a magnetic resonance system, a computed tomography system, an X-ray system or an ultrasound system. When, for example, the head of a patient is to be examined, this is registered in the form of a number of individual tomograms. An examination volume of a subject is registered, i.e. the digital image dataset that is obtained contains not only information about the exterior of the subject but also about of the internal subject volume. As a result, it is possible, for example, to display a head exposure in the form of a volume image, for example as a projection image or as surface image, in three-dimensional form. It is then important for the physician to obtain as much information as possible in an optimally simple way on the basis of the registered images.
An object of the present invention is to provide a method and apparatus wherein images are displayed at a display monitor that enable the viewer to make an analysis in a simple and surveyable way.
This object is inventively provided in a method (and an apparatus, described below) wherein at least two images of the examination volume with arbitrary orientation of the image planes relative to one another are simultaneously displayed at the display monitor, and wherein at least one marker is displayed in each image that indicates information about the position of the image plane of the other image relative to the image in which the marker is displayed.
According to the inventive method, a number of images of the examination volume, i.e. of the registered subject, are played back at the display monitor, respectively in different image planes, for example, the planes can reside perpendicularly relative to one another, so that the physician obtains an image display in the form of a horizontal section through the examination volume and the other image shows a vertical section. In addition, the physician is provided with information about the image plane setting of the individual images relative to one another in the form of the markings that are mixed into the respective images, so that it is easy for the physician to recognize how the images being displayed are arranged with respect to one another. The physician thus can link the informational contents of the displayed images with one another since each image supplies the physician with a reference to the other image. Inventively, three images can be played back at the monitor, with each image containing two markers relating to the image plane position of the two other images to the image containing the markers. An even greater presentation of information thereby can be achieved.
Inventively, various markers can be employed dependent on the position of the image planes, with a first marker being employed when the image planes reside perpendicularly to one another, and a second marker being employed when the images reside at an angle other than 90xc2x0 relative to one another. Lines can be displayed as the markers, these markers proceeding substantially over the entire image. When two different markers are employed, the first can be displayed as a solid line and the second can be displayed as a broken line, preferably dashed, or conversely, as long as it is assured that the physician can easily distinguish between the markers.
When more than two images are displayed, it has proven advantageous when an image-specific identifier or a symbol is allocated to each image, with each marker belonging to this image and reproduced in another image likewise showing this identifier or a symbol is allocated thereto, so that a simple reference between a marker displayed in a first image, for example a line, and the appertaining image whose plane orientation is to be indicated, is possible. It has proven essentially expedient to allocate a specific color to each image such as an identifier, particularly in the form of a color frame surrounding the image, with the appertaining marker likewise being reproduced with this color. When, for example, three separate images are used, the first image can exhibit a red frame, the second image a green frame and the third image a blue frame, with a green line and a blue line for indicating the positions of the planes of the second and third images are mixed into the first image, a red line and a blue line for indicating the planes of the first and third images are mixed into the second image, and a red line and a green line referring to first and second images are mixed into the third image.
It has also proven advantageous to provide an auxiliary marking for each line, indicating the direction of view from which the image allocated to the marker is viewed with reference to the image into which that marker is mixed. The auxiliary marker can be in the form of an arrow allocated to the respective line.
Inventively, additional information about the location-related position of the image plane of an image with respect to another image can be provided by means of the marker, for example, where the sectional view through the presentation shown in the first image is the shown, for example, in the second image, position-indicating lines can also be included in the second image. To this end, the respective lines in each image can be presented laterally-shifted or vertically-shifted in an especially simple way, so that the position of the individual images relative to one another can be indicated in a simple way.
So that the physician can evaluate the examination volume in an arbitrary presentation, the orientation of the image plane of an image, and thus the view of the image, can be inventively modified given a correspondingly adapted presentation of the markers. For example, the physician can tilt or rotate a projection image shown as the third image in order to be able to observe the examination volume at a different viewing angle, with the corresponding markers also being automatically adapted or re-adjusted. The modification can expediently ensue by moving the markers, particularly shifting or rotating the lines with a suitable control unit, such as a control mouse. For example, example, a line movement can be accompanied by a modification of the image or presentation. Alternatively or additionally, the modifications of the image plane orientation can ensue with a track ball or the like, i.e. the image presentations themselves are modified and the presentation of the marker is correspondingly adapted. As described, volume images in the form of projection images or surface images or tomograms can be reproduced. The type of image to be reproduced can be selectable, i.e. the user can select whether, for example, projection images or tomograms are to be displayed. The markers always supply the user/viewer with the corresponding information independently of the type of image selected. Different types of image can be simultaneously displayed.
As noted above, the invention is also directed to an apparatus for processing and playback of digital images. The inventive apparatus has an image processor in which the digital image data of an examination volume of a subject are present, and a display monitor for the playback of an image. The apparatus inventively displays at least two images of an examination volume with arbitrary orientation of the image planes relative to one another at the display monitor, and in that the image processor is xe2x80x9cfashionedxe2x80x9d for generating markers reproducible in the images, with each image containing at least one marker that indicates information about the position of the image plane of the other image with respect to the image in which the marker is displayed. The inventive image processor, which can be a computer means that is capable of processing the digital image data transmitted to it, is designed for generating the respective markers, as well as for reproducing a number of different images at the display monitor. Three images can be reproducible at the display monitor, with the image processor being fashioned for generating and displaying two markers in each image that identify the respective image plane position of the two other images. Further, the image processor can be designed for generating various markers whose type is dependent on the attitude of the image planes. A first marker is employed when, for example, the image planes reside perpendicularly relative to one another; a second marker different in nature from the first marker is employed when the planes reside at an angle other than 90xc2x0, Lines that proceed across substantially the entire image can be expediently displayed as the markers. These can be solid or, when different markers are employed, can be broken, for example dashed.
For facilitating the allocation of a marker to a respective image whose plane attitude is to be indicated by the marker (problems occur when four or more images are displayed), the image processor can inventively allocate an image-specific identifier or a symbol for each image, and can likewise allocate this identifier or the symbol to every marker belonging to this image and reproducible in another image. The image processor generates corresponding identifiers or symbols, whereby a specific color, especially in the form of a color frame surrounding the image, is particularly expedient as the image-specific identifier; the appertaining marking is then reproducible in precisely this color. For indicating location-related information in view of the position of the image plane with reference to the presentation of another image, the image processor can also be fashioned for generating markers that additionally contain an information about the location-related position of the image plane of the respective image with respect to a different image, for example in the form of lines displayable side-shifted or height-shifted. Further, it has proven especially expedient for example, the image processor to generate at least one auxiliary marker for each marker, particularly each line, that indicates the direction of view from which the image allocated to the marker is reproduced with reference to the image in which the marker is displayed, particularly in the form of arrows allocated to the line, so that the physician can unproblematically recognize the direction from which the reference image identified by the marking is being viewed relative to the image in which the marking is displayed.
Inventively, further, the orientation of the image plane of an image, and thus the view of the image, is variable given correspondingly adapted presentation of the markers. This can ensue according to a first embodiment of the invention by shifting or moving the markers, i.e. the image presentation here follows the line displacement. Additionally or alternatively, a track ball can be provided with which the image orientation of an image is variable, with the markers being correspondingly modified.
The invention is also directed to a medical examination installation having an image pickup system for registering image data of an examination subject, as well as a device of the aforementioned type to which the image data can be provided in digital form.